Artificial feed for silkworms and method of using the same

ABSTRACT

SILKWORMS HAVING COMPLETED AT LEAST THE SECOND INSTAR STAGE CAN BE RAISED SUCCESSFULLY ON A GELATINOUS, WATERBEARING FEED CONTAINING MAIZE AND/OR SORGHUM WITH SOY BEEN SOLIDS AS THE PRINCIPAL NUTRITIVE INGREDIENT EVEN IF THE COMBINED AMOUNT OF THE MAIZE AND/OR SORGHUM WITH SOY BEAN SOLIDS EXCEEDS 50% OF THE DRY FEED WEIGHT AND THE FEED IS FREE FROM MULBERRY LEAVES OR FEED PRODUCTS CONTAINING MULBERRY LEAF SOLIDS. MINOR AMOUNTS OF MIXED ANTIBIOTICS, WHEN ADDED TO THE FEED, PROTECT THE SILKWORM LARVAE FROM FLACHERIE.

United States Patent O 3,583,871 ARTIFICIAL FEED FOR SILKWORMS AND METHOD OF USING THE SAME Masazumi Niimura, Kamakura-shi, Shigeo Matsubara,

Kawasaki-shi, and Takehisa Sakakibara and Jim Kirimura, Tokyo, Japan, assignors to 'Ajinomoto Co., Inc., and Katakura Industry Co., Ltd., both of Tokyo, Japan No Drawing. Filed Apr. 1, 1968, Ser. No. 717,946 Int. Cl. A23k 1/00; A233 1/14 US. Cl. 99-2 ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to silkworm feed and to a method of raising silkworms.

It has been proposed heretofore to raise silkworms on feed other than mulberry leaves, and such feeds will be referred to hereinafter as artificial feeds. However, the known types of artificial feed are inferior to natural 9 Claims 'ice connected with a sensing spindle against which a sample of feed is raised on a movable plate at a uniform rate and without vibration. Hardness is measured at 20 C. and is shown on a balance scale in dyne/cmf We have succeeded in raising newly hatched silkworm larvae at least up to 2nd instar on an artificial feed containing soy bean solids and maize and/or sorghum with a small amount of mulberry leaves, and thereafter on an artificial feed containing soy bean solids and maize and/or sorghum without mulberry leaves or mulberry leaf solids.

'The maize used for this invention is derived from thef ruit of millet corn, or Indian corn, Zea mays L, including dental corn, flint corn, waxy corn and lysinerich corn. Sorghum is Sorghum vulgare and includes guinea corn, kaoliang, milo, grain sorghum and kafir.

Whole kernels of maize or sorghum are crushed to particles which pass through a 10 mesh screen and preferably a 50 mesh screen. The combined amount of maize, sorghum, 'and soybean in the feed of the invention is 50% or more, preferably 85-97% by weight on a dry basis, and it may also be desirable to add small amounts of known supplemental ingredients of artificial silkworm feeds such as sterols, vitamins and minerals, also starch and cellulose powder. The ratio of maize and sorghum to soybeans should be between 1:9 and 9:1 by weight,

. preferably between 1:1 and 4: 1. If necessary, corn starch is added for proper consistency of the feed and is heated with the aqueous mixture to 100 C. for about 5-40 min. to form a hydrogel on cooling.

The artificial feed of this invention is not limited in mulberry leaves in promoting the growth of the silkworm larvae and in the weight of the cocoons produced.

SUMMARY OF THE INVENTION We have now found that the silkworm, which was considered for a long time a monoph'agous insect eating""" only mulberry leaves, also eats maize and/or sorghum, and that an artificial feed containing maize and/or sorghum may be enriched with soybeans as an additional protein source. Silkworm larvae raised on the artificial feed of the invention produce cocoons of good weight.

While maize or sorghum have been used asa general animal feed, attempts at raising silkworm larvae on maize or sorghum have not been made heretofore.

It has been found that the newly hatched larvae are mulberry leaf solids. However, the feeding habits of silkworm larvae can be changed during their growth, and the larvae eat an artificial feed containing 50-90% water if in a gelatinous state and having a hardness of 10*10' dyne/cm. (20 C.) as measured with a curd tension meter produced by Iio Electric Co., Tokyo, Japan,

.. and each feed mixture was cooked for 20 min. at 100 C to all useful insects belonging to the families Bombycidae and Saturuniidae, such as Bombyx mori, Philoramia synthia ricini, Anthereae pernyi, Anthereae mylitm and A nthereae yamamai.

DESCRIPTION OF PREFERRED EMBODIMENTS Example 1 Five groups of newly hatched silkworm larvae of the species Bombyx mori were raised up to their 4th instar on the artificial feed shown in Table I, and from the 5th instar stage on respective artificial feed compositions shown in Table II at 23 C. at relative humidity. All the feed particles passed through an '80 mesh screen,

Forty silkworms were in each group.

.type reported by T. Ito (The Journal of Sericultural Science of Japan (in Japanese) 31, 73 (1962)) and feed C was of the type reported by Y. Hamamura et al. (The Journal of the Agricultural Chemical Society of Japan (in Japanese), 37, 736 (1963)).

TABLE I TABLE IV D-2 D-3 D4 Mulberry leaf powder 1O 5 D t 1 Defatted soybean meal Mil. igfiiffifilliiiijiiiij 2?, 32 2?. 32 Dental corn 12 Defatted soybean meal (g.) 25 25 25 25 A ar 10 Trace nutrients (g.) 5 5 5 5 g Water (g.) 300 300 300 so Soybean 011 3 goo kn ig ime a 100; 0. (gain). 50 0. 5 2% 2o ar ic e size corn mes .1... 0 0 80 Trace nutnents 1 10 Hardness (dynes/cmfl at 0.). 7.s 10 7. 8x10 s.1 1u 2 4 1o Water 300 0.3 g. soybean sterol, 1 g. citric acid, 1.5 g. minerals, 2 g. vitamic C, and 0.2 g. vitamin B complex. Also used in other examples.

TABLE II A-l A-2 A-B B C Dental corn (g.) 45 40 Milo (g. Mulberry leaf powder (g.)- Cellulose powder (g.) 52 Defatted soybean meal (g.) 20 Starch (g) 10 15 Glucose (g)..- 5 Saccharose (g.) 10 Trace nutrients (g.) Vitamin B complex (g.) 0.1 Vitamin G (g.) 0.4 Chlorogenic acid (g.) 1 Minerals (g) 0.9 fi-Sitostcrol (g.) 0.5 Innositol (g.). 0.5 Water (g.) .0 Hardness (dynes/c TABLE V D-l D-2 D-3 D-4 Average Weight of fully-grown silkworms (g.) 5. 6 1. 5 2. 3 1. 3 Larvae spinning cocoon (percent) 100. 0 0. 0 2. 5 5. 0 TABLE III Average weight of cocoon layer (g.) 0. 43 0. 06 0.07 A-l A-2 A-3 B 0 Average weight of fully-grown silkworms M 3-2 M M m 40 The results listed 1n Table show the importanceof Larvae spinning cocoon (percent). 100.0 80.0 87. 5 70.0 30.0 the method for P p g 531d feed, mg cooklng Average Welght of cocmnlayer conditions, the size of the corn particles and moisture on The results obtained are shown in Table III.

Example II the growth of the larvae and the quality of the cocoons.

Example III Ten groups of newly hatched silkworm larvae were raised up to their 3rd instar on the artificial feed of Table I and thereafter seven groups of larvae at the 4th instar stage were raised respectively on the feed compositions shown in Table VI. All the feed particles of these compositions passed through an mesh screen, and the com positions were cooked 30 minutes at C.

The 8th, 9th and 10th groups of larvae were respectively raised on feed B, C (see Table II) and F (only mulberry leaves). Forty silkworms were in each group and were raised at 25 C., 70% relative humidity.

TABLE VI E1 E-2 E-3 E-4 E-5 E-fi E-7 Dental corn (g.) 25 40 3O 65 25 2 0 Milo 50 20 15 65 25 10 Deiatted soybean me 20 35 50 30 30 25 20 Trace nutrients (g.) 5 5 5 5 5 5 5 Corn starch (g 20 25 Cellulose powder 20 Water (g.) 300 300 300 300 300 300 300 Hardness (dyncs/c at 20 0.)- 8.7)(10 7.2X10= 9. 0X10 8. 6X10 8. 3x10: 8. 6X10 6. 4x10 The results obtained are shown in Table V II.

TABLE VII E-l E-2 E-3 E-4 E5 E-6 E-7 B C F Avera e weight of melting larvae in 3rd instar Avera e weight of melting larvae in 4th instar (mg. 841 872 848 827 830 803 795 560 503 795 Average weight of fully grown silkworms (g.) 5. 4 6. 1 5. 8 5. 1 5.0 4. 3 4. 5 3. 2 2. 0 4.0 Larvae spinning cocoon (percent) 100 100 100 98 98 95 95 78 35 93 Average weight of coccon (g.) 2.5 3.0 2. 7 2. 8 2. 6 2.4 2. 3 1.3 0. 01 1. 6 0. 40 0. 46 0. 42 0. 43 0. 41 0. 39 0.38 0. 22 0.10 0. 38

Average weight of cocoon layer (percent) Penicillin plus picromycin It has further been found that the silkworm larvae were protected against fiacherie due to alkalophilic lactic acid bacteria (such as Streptococcus faecalis, Streptococcus faecium var mobilis and Lactobacillus), if the feed of the invention contained penicillin, tetracycline, oxytetracycline, chlorotetracycline, together with a macrolide antibiotic such as erythromycin, leucomycin, oleandmycin, picromycin, methymycin, carbomycin or spiramycin. The combined antibiotics should generally amount to 0.1- 0.001% of the feed on a dry basis to prevent or cure fiacherie.

Example IV Antibiotics were added to the feed E-Z (see Table VI) Penicillin and other antibiotics were combined in respective amounts of '60 units/ gr. dry feed and 0.1 mg./ gr. dry feed. When only one antibiotic was used, the dosage was twice the respective amount. Alkalophilic lactic acid bacteria were inoculated into the feed compositions. Groups of ten silkworms (newly molted th instar) were raised aseptically on the several compositions for 7 days at 25 C., at 70% relative humidity. Table VIII lists the average body weight of the 7-day old Sth-instar larvae, and the count of pathogenic bacterial cells in one gram of their feces on the following scale:

+++=more than cells i 1-10 cells =I1OI16 TABLE VIII Number Average bacterial weight (g.) ls

Streptomycin 1. 85 Penicillin 3. 01 Tetracycline 3 08 Ghloramphenicol 3 10 Erythromycim. 3 Lcucomycin. 5 Picromycin 0 Carbomycim. Oleandmycin 4 Penicillin plus kanamycin 9 Penicillin plus tetracycline. 2

Penicillin plus erythromycin Penicillin plus leucomycin Penicillin plus oleandmyc Penicillin plus methymycin Penicillin plus spiramycin Penicillin plus carbomycin- Tetracycline plus erythromyci Tetracycline plus lcucomycim. Tetracycline plus oleandmycin. Tetracycline plus picromycin Penicillin plus leucomycin plus oxytetracycline. Penicillin plus olcandmycin plus oxytetracycline- Tetracycline plus leucomycin plus oleandmycin Tetracycline plus erythromycin plus chloramphenicol.

We claim:

1. A feed composition for silkworms essentially consisting of a hydrogel containing at least on a dry basis of soy bean solids and nutritive material selected from the group consisting of maize, guinea corn, kaoliang, milo, grain sorghum, and kafia, the hardness of said hydrogel being 10 to 10 dyne/cm. at 20 C.

2. A composition as set forth in claim 1, wherein the amount of said soy bean solids is between and 9 times the amount of said nutritive material on said dry basis.

3. A composition as set forth in claim 2 which is free from mulberry leaf solids.

4. A composition as set forth in claim 1 containing a first antibiotic selected from the group consisting of penicillin, tetracycline, oxytetracycline, and chlorotetracycline, and a second antibiotic which is a macrolide, the respective amounts of said first and second antibiotics being sufficient to protect silkworms from flacherie when said silkworms feed on said composition, and the combined amount of said first and second antibiotics being between 0.1 and 0.001 percent of said composition on said dry basis.

5. A method of raising silkworms which comprises feeding said silkworms the feed composition of claim 1.

6. A method of raising silkworms which comprises feeding said silkworms the feed composition of claim 2.

7. A method of raising silkworms which comprises feeding said silkworms the feed composition of claim 3.

8. A method as set forth in claim 7, 'wherein said silkworms have at least completed the second instar stage.

9. A method of raising silkworms which comprises feeding said silkworms the feed composition of claim 4.

References Cited UNITED STATES PATENTS 3,093,483 6/1963 Ishler et a1. 99131 3,275,446 9/1 966' Hamamura et a1. 992 3,155,520 1/1964 Ziifer 992 3,230,930 1/ 1966 Hamamura et al 992 3,244,527 4/ 1966 Baker 992 3,328,170 6/1967 Hamamura et al. 992 3,425,838 2/ 1969 Kamada 992 3,465,721 9/ 1969 Miyazawa 99-2 3,488,196 1/ 1970 Niimura 992 NORMAN YUDKOFF, Primary Examiner C. P. RIBANDO, Assistant Examiner US. Cl. X.R. 

